Probable cause
A loss of engine power due to the number four cylinder base nuts becoming loose, allowing the cylinder to detach from the engine case. Contributing to the accident was the pilot's impaired visibility due to smoke during the forced landing.
NTSB analysis
While en route to an agriculture application job, the airplane's engine exhaust started shaking, then smoke started coming off the engine. The pilot landed on a farm road. During the landing his visibility was limited by the smoke, and the right wheel went off the road into soft mud. The airplane swerved to the right and nosed over. Examination of the engine disclosed that the number four cylinder base nuts had backed off, allowing the cylinder to separate from the engine case.
Text from the NTSB. Open the NTSB docket for WPR09CA114 for the full record.
Event
- Date
- Feb 12, 2009
- Type
- Accident
- Place
- Buttonwillow, California
- Highest injury
- None
- Weather
- Visual (VMC)
- Light
- Day
Schweizer G-164B
- N-number
- N3626T
- Category
- Airplane
- Damage
- Substantial
- Operating rule
- Part 137 (agricultural)
- Purpose of flight
- Aerial application
From the NTSB aviation accident database: N-registered aircraft, events since 2008, data through Oct 28, 2026. The file is published monthly, so the latest weeks are incomplete and recent records can change. The official source is the NTSB aviation investigation search. CheckAero is independent and not affiliated with the NTSB.